Sealant mixer and dispenser



Oct. 30, 1956 J. L. WEAVER Filed Aug. 17, 1953 2 Sheets-Sheet 1 Z; [My 3 v i 5 A? 75" F7' m \m I 40 V I A-V 37 6664 6334 INVENTOR,

JOHN L M54 1/52 ATTORNEY Oct. 30, 1956 J. I... WEAVER 7 2,768,315

SEALANT MIXER AND DISPENSER Filed Aug. 17, 1953 2 Sheets-Sheet 2 INVENTOR, /06 JOHN L. 11 54 1/52 ATTORNEYS.

United Sttes Patent SEALANT MIXER AND DISPENSER John L. Weaver, San Diego, Calif., assiguor to Coast Pro- Seal & Manufacturing Co., Los Angeles, Calif., a corporation of California Application August 17, 1953, Serial No. 374,672

15 Claims. (Cl. 259-43) This invention relates to apparatus for mixing viscous sealing compounds.

The constituents of the mixing compound are a rubber-like synthetic material and a catalyzer. When mixed, the compound begins to set at a rate dependent upon the temperature thereof. The compound may be applied to abutting or overlapping metal parts, such as aircraft fuel tank parts.

In order that the compound be easily applied to the work, substantial setting of the compound prior to use must be avoided. Thus, the compoud must be maintained as cool as possible and be mixed only shortly in advance of the time at which the compound is applied.

It is an object of this invention to provide an improved portable mixer for a compound of this character.

It is another object of this invention to provide improved means for maintaining the compound cool during the mixing operation. A hollow rotary member is provided with a series of helically arranged interrupted projections cooperating with a cylindrical wall of a nonrotary member, the constituent material being supplied in definite proportions between the rotary and non-rotary members for intimate intermixture. A fluid coolant, such as air, is passed axially through the hollow rotary member to conduct heat from the rotary member and the sealing compounds with which it is in contact. The heat passes generally radially inwardly of the rotary member to maintain the compound cool. The interrupted projections serve not only as a means for causing intermixture of the constituents, but also to enhance the rate of heat dissipation, since these projections provide substantial areas of engagement with the compound for conducting heat therefrom.

The mixer may be used intermittently, and unavoidably some partially mixed constituents may remain in the mixing chamber when the mixer is not in use. The constituents may clog the mixer, requiring cleaning of parts. It is, accordingly, another object of this invention to provide a mixer in which the rotary mixer is readily removable and the non-rotary member cooperating with the mixer is readily accessible for cleaning. For this purpose, a novel arrangement of parts is provided, including a detachable connection between the mixer and the source of rotary motion therefor.

It is another object of this invention to provide a simple and compact apparatus for ensuring accurate relative rates of feeding the constituent materials to the mixing chamber. For this purpose, concentric cylinders are provided defining spaces for accommodating the constituents.

It is another object of this invention to provide an improved apparatus for feeding the constituent materials to the mixing chamber under sufficiently high and controlled pressure to ensure substantial and uniform flow of the constituents through the sinuous paths around the projections of the mixer. For this purpose, use is made of an hydraulic system supplying fluid under pressure to pistons in the concentric chambers. An appropriate 2 pressure relief mechanism is incorporated in the system to control within narrow limits the pressure applied to the constituents through the pistons.

It is another object of this invention to provide an extremely compact hydraulic system for mixing apparatus of this character.

It is another object of this invention to provide a control valve for selectively controlling the direction of movement of the pistons under the influence of the hy' draulic system whereby reverse movement of the piston can be availed of for pumping the constituents into their respective chambers for filling the same.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose, there is shown a form in the drawings accompanying and forming part of the present specification. This form will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a side elevation of a device incorporating the present invention, a portion of the apparatus being shown in section;

Fig. 2 is an enlarged fragmentary sectional view, taken along the plane indicated by line 22 of Fig. 1; and

Fig. 3 is a fragmentary sectional view, taken along the plane indicated by line 33 of Fig. 1.

The sealing compound with which this invention is concerned is a viscous tacky material that begins to set or harden as soon as it is formed and at a rate dependent upon its temperature. It is thus important that the sealing compound be prepared shortly in advance of its intended use and that it be kept cool in order that the sealing compound be easily and efi'fectively used.

The constituent materials to be mixed are accommodated in a cylindrical casing 16) Which is secured to one side of a plate 11. Concentric annular spaces 12 and 13 for the constituent materials are formed by a hollow control cylinder 14 and an intermediate cylindrical wall 15, both secured to the plate 11 within the casing 10.

A pair of annular pistons 16 and 17 defines the outer limits of the annular chambers 12 and 13. These annular pistons 16 and 17 are movable in unison and in accordance with the position of a control piston 18. For this purpose, a disc 19, guidingly received in the open end of the cylindrical casing 10, mounts the elongate studs 20 which secure the annular pistons 16 and 17, as well as the control piston 18, to the disc 19.

The constituent materials from the annular spaces 12 and 13 are urged by the pistons 16 and 17 to a mixing chamber 21. The mixing chamber 21 is formed by an end opening cylindrical recess 22 in a body structure 23. The body structure 23 may be detachably secured on the other side of the plate 11 by a clamp 23 secured by a pair of clamping bolts 24.

The body 23 provides a pair of right angled passageways 28 and 29 establishing communication from the respective annular spaces 12 and 13 of the upper end of the cylindrical recess 22. The passageways 28 and 29 discharge into the chamber 21 at diametrically opposite portions of the recess 22, and respectively communicate with the inner and outer annular spaces 12 and 13 via appropriately located ports in the plate 11.

The annular pistons 16 and 17, being movable in unison, ensure that a constant proper proportion of the constituent materials is delivered to the mixing chamber 21. By appropriate proportioning of the cylinder spaces 12 and 13, the ratio of delivery of the constituents may be determined. For the proportions shown, the volumes of delivery are substantially equal, since the areas of the annuli 12 and 13 are substantially the same.

The control piston '18, connected to the pistons 16 and 17, is acted upon by fluid pressure for moving the annular pistons 16 and 1-7 as desired.

A centrally :apertured cap30, threadedly accommo' dated on the outer end of the control cylinder -1 4,"closesone. end of the control cylinder 14. A transverse wall or head '32, spaced slightly inwardly of the control cylinder 14 from the plate 11, is 'located at the other'end" of the cylinder'14. The cap Sit-and wail32 cooperate with the cylinder 14 to define chambers 31 and 33 on opposite sides of the piston 18.-

Fluid'under pressure is selectively conducted-either to the space 3 1 or '33 for applying motive force to the control piston 18 in one direction or the other.

A port forming member 35, extending transversely of the plate 11 and intermediate wall 32, communicates with the space 33. A port forming member 34, extending transversely of the plate 11, establishescommunication with the space 31 via the space 36 formed between the plate 11 and the inter-mediate wall 32, and a series of elongate passages 37 formed in the walls of the control cylinder '14, the elongate passages 37 communicating with the spaces 36 and 31 via appropriate oblique ports 38. 'Conveniently, the wall of the cylinder 14 may be formed of two telescoping members appropriately formed to define theelongate passageways 37 An hydraulic apparatus, formed in a cylinder block 39, appropriately supplies fluid under pressure to the space 31 or 33. The cylinder block 39 is detach-ably secured to the plate 11 in a suitable manner.

A through vertical recess 41 of the block 39 is filled with fluid (such as oil) and forms a return or-supply space 44 for the hydraulic fluid. The return space 44 is filled via a transverse aperture 47 of the block 39 that opens laterally exteriorly of the block 39.

A side plate '48, extending over the open end of therecess47, accommodates a filler plug 49. The filler plug 49 closes an aperture 50 in the plate '48 thatcommunicates with the recess 47. A shank 51 of the plug 49 conveniently mounts a bulb or bladder 52 formedof flexible material which may serve as a means for permitting thermal expansion of the fluid in the system.

A rotary shaft 40 for operating the mixer and hydraulic apparatus extends with substantial clearance vertically into and beyond the through recess -41 formed in the block 39; Suitable bearing structures '42 and 4'3, accommodated in opposite ends of the recess 41, rotatably mount the shaft 40.

End brackets 45 and 46 seal the ends of the recess 41.

Fluid is urged under pressure to a slide valve chamber formed by an elongate recess 53 of the block 39.

Fluid passes from the supply space 44 through a reciprocable piston 54 in a piston chamber formed by a recess 55 of the block 39, through a passageway 56 communicating with the piston cylinder chamber, an enlarged end opening recess 57, past a check valve structure 58 in the recess '57, and thence through passages '59, 60 and 61, the last mentioned passageway openinginto the slide valve recess 53.

Also opening into the slide valverecess 53 are motor ports 62 and 63 communicating, respectively, with the port forming members '34 and 35 and thence to the control cylinder spaces 33 and '31. A longitudinally movable slide 64, guidingly accommodated in the recess5'3-and extending beyond the upper end thereof, serves as a means for establishing communication between the port 61 froin the supply space 44 to either of the motor ports.

For this purpose, the slide 64 has three longitudinally spaced annular recesses 65, 66 and 67. The intermediate annular recess 66 continuously communicates with the pressure passageway 61 throughout the range of movement of the slide 64. Return .ports 68 and 76,- openinginto the return space 44, continuously communicate with 4 the end annular recesses 65 and 67, respectively, throughout the range of movement of the slide 64.

The motor ports 62 and 63 are situated intermediate the pressure port 61 and the respective return ports 76 and 68. Each motor port 62 or 63 may be placed in registry either with its corresponding end annular recess 67, 65, or with the intermediate annular recess 66, all depending upon the position of the slide 64.

Accordingly, in the lower position of the slide 64 shown, the motor port 62 registers with the intermediate annular recess 66 to receive fluid under pressure from the pressure passageway 61; the upper motor port 63 is in communication with the annular recess 65 and the return space 44;- Accordingly, the outer space 31 on one side of the control piston 18 is pressurized, and the inner space 33 on the other side of the piston 18 is exhausted. The piston is urged toward the plate 11, and the annular pistons 16 and 17 urge the constituent materials to the mixingchamber 21.

Correspondingly, in the upper position of the slide 64, the motor port 63 moves into registry with the intermediate annular recess 66'and out of registry with the upper annular recess 65. The other motor port 6'2 moves out of registry with the intermediate annular recess 66 and into registry with the end annular recess 67.

Accordingly, in the upper position of the slide 64, the motor passageway 63 communicating with the inner space 33 is supplied with pressure; and the other motor passageway 62 communicating with the outer space 31 is exhausted. The pistons are thus urged to retracted position.

The retracting movement of the pistons '16, 17 and 18 serves to draw material into the annular spaces 12 and 13. Filling apertures for the spaces 12 and 13 extend through the plate 11. These apertures are normally closed by plugs 25 and 26.

Theupper end of the slide 64 projects through the sealing plate 46. This end of the slide 64 has interrupted threads 30 that are engaged by a thumb nut 31. The thumb nut 81'is confined against axial movement by a plate 83. Accordingly, the thumb nut 81 serves as a means for adjusting the longitudinal position of the slide 64.

The slide 64is held against rotation by a recess 84 of the upperplate 83 through which it passes, the recess 84"being non-annular and corresponding to the periphery of the interruptedly threaded end of the slide 64.

The piston 54 urges fluid under pressure to the passageway 61'0p6ning into the slide valve recess. The piston 54 is guidingly accommodated in the cylinder recess 55 and is reciprocated by the aid of a cam 69 carried by or formed integrally with the rotary shaft 46.

The piston 54 is maintained in following relationship with the'cam 69 by the aid of a helical compression spring 70 engaging at respective opposite ends the piston 54 and a cap 71 closing the outer opening of the cylinder chamber 55.

The cylinder 54 has axial ports 72 and 73 at opposite ends communicating with an enlarged central chamber 74 of the piston 54.

A ball 'check valve structure 75 is accommodated in the recess, and cooperates with that port 73 of thepiston 54 which communicates with the supply space 44.

As the piston 54 movesinwardly toward the axis of the shaft 40, fluid is drawn from the supply space 44 through the port 73, past-the ball check valve structure 75, and into the'cylinder chamber 55. When the piston 54 moves radially outwardly away from the axis of the shaft 4t),"the check valve 75 traps the fluid in the cylinder, preventing return of fluid to the supply space 44. As the piston 54 moves in this direction, fluid is urgedfrcm the piston chamber '54' to the passageway 56 leading to the slide 'valve chamber. Since cam 653 has a narrow or line contact with piston 54,"the port 73 is in continuous communication with chamber 44.-

The check valve structure 58 prevents reverse flow back to the cylinder 55, ensuring proper intake when the piston 54 moves toward the shaft 40.

A by-pass valve for limiting the pressure of the system is provided. For this purpose, passageways 90 and 91 are provided. The passageway 90 is in continuous communication with the outlet passageway 56 from the piston chamber 55 across the recess 57 in which the check valve 58 is accommodated. The passageway 91 opens into the return space 44.

The by-pass is efiective only when the pressure from the outlet of the cylinder chamber reaches a predetermined value, such as might be caused by an increased load on the constituent moving pistons 16 and 17. To accomplish this function, a check valve structure 92 is interposed between the passageways 90 and 91. This check valve structure 92 is closed during normal operation of the system. However, when the piston structures 16, 17 and 18 arrive at either of their limiting positions while shaft 40 continues to rotate, this check valve structure permits circulation around the pump 54-55 without forcing fluid to the cylinder 14.

The shaft 40 is rotated by the aid of an air motor 85 secured to the plate 11. The air motor 85 has an output shaft rotatable about an axis normal to the axis .of rotation of the operating shaft 40.

A driving connection is effected between the air motor 85 and the shaft 4-0 by the aid of bevel gear structures 86 and 87. The bevel gears 86 and 87 are so arranged that removal either of the air motor 85 or the block 39 from the plate 11 is rendered simple.

A rotary hollow mixer or chopper 100 is accommodated in the recess 22 of the body 23. The mixer 100 has a shank portion 101 extending upwardly of the body 23. An axially separable connection 102103 is effected between the shaft 40 and the mixer 101 so that the shaft 40 serves as a common means for operating the pump 54-55 as well as the mixer 100.

The operative portion of the mixer 100 has a series of peripheral projections 104 arranged spirally generally as interrupted threads. These projections 104 have but slight clearance with respect to the cylindrical recess 22 of the body 23. The material from the passageways 28 and 29 leading into the bottom of the recess 22 passes between the small spaces defined by the projections 104 and the cylindrical recess 22.

While the projections 104 are arranged generally helically, the angular direction of the helix may be such as to induce a slight reverse flow of the constituent materials. This produces a slight churning action, aiding the intermixture of the materials.

The projections 104 are interrupted in such manner that the spaced between adjacent projections are not all axially aligned. Accordingly, there are restraints in the path of direct axial movement of the material. Such arrangement causes changes in direction of the flow of the constituent materials, further aiding in the mixing operation. When the materials finally reach the bottom of the mixer 100, they are mixed to a substantially homogeneous consistency.

A cap 105, threadedly accommodated on the end of the body 23, collects the material passing the end of the mixer 100. For this purpose, oblique passageways 106 are provided, each communicating with an outlet 107 of the cap 105. A suitable nozzle or hose (not shown) may be connected to the outlet 107 for appropriately directing the sealing compound.

The space or chamber 100 defined by the hollow mixer 100 opens outwardly of the mixer 100, axially through a port 109 in the end wall 110 thereof.

The cap 105 cooperates with the mixer 100 to isolate the space 103 within the mixer 100 from the space in which the mixed constituents are located. For this purpose, the end wall 110 of the mixer has integrally formed thereon a depending annular wall 111 that is in annular 6 sealing engagement with a yielding member 112 carried by the cap 105.

Air for cooling the mixer structure 100 is passed into the space 108 within the mixer 100 and thence outwardly of the structure. For this purpose, the outlet of the air motor is connected to the mixer space 108 by the aid of a conduit 113. The conduit 113 registers with the passage 114 in the body 23 through the plate 11. The body passage 114 opens into the recess in which the shank 101 of the mixer is accommodated. An annular space formed by a peripheral groove 115 on the shank 101 of the rotary mixer continuously communicates with the inlet passage 114.

Diametric and axial passages 116 establish communication between the annular space formed by the groove 115 and the chamber 108 Within the mixer 100. The cap has a series of oblique passages 117 that are in registry with the port 109 to conduct the air out of the chamber 100.

The large area provided by the projections 104- of the mixer 100 materially aids the passage of heat from the constituents to the interior of the mixer 100 to be conducted outwardly by the passage of air. The passage of air through the mixer maintains the constituent materials at a low temperature. By maintaining the constituents cool, the setting of the constituents is retarded.

Accordingly, the sealing compound is in substantially a fluid though viscous state when applied to the work. Maintaining the mixed constituents in the mixing chamber cool also lessens clogging of the apparatus.

The mixing apparatus can easily be removed for purposes of cleaning. The rotary mixer can be removed simply by removing the cap 105. If desired, the entire mixer body 23 can be disassembled for purposes of cleaning passages by loosening the clamping bolts 24.

The inventor claims:

1. In a mixing apparatus: a plate; an elongate outer shell having a uniform inner surface and carried at one end by the plate; an elongate inner shell having a uniform cross section and extending within the outer shell and carried at one end by said plate; said shells defining separate spaces for constituent materials; a pair of pistons guidingly accommodated in the other ends of said shells; a support mounting both of said pistons for movement in unison; means carried by the plate and forming a mixing chamber; means for conducting material from said spaces to said mixing chamber; and means for advancing and retracting said pistons.

2. In a mixing apparatus: a non-rotary outer shell; a non-rotary inner shell supported within the outer shell; a control cylinder supported Within the inner shell; said inner and outer shells defining a first space for a constituent to be mixed; said control cylinder and said inner shell defining a second space for another constituent material; a pair of pistons accommodated in the spaces respectively; a control piston cooperating with the control cylinder; and means interconnecting all of the pistons for movement in unison.

3. In a mixing apparatus: a body having an exteriorly opening recess forming a mixing chamber; a rotary hollow mixer in the chamber; a closure for the recess; means preventing communication between the hollow interior of the mixer and the space between the mixer and the chamber wall; means for conducting constituent materials to the bottom of the recess in communication with said space; means for conducting a cooling fluid into the interior of said mixer; and separate passage forming means provided in said closure for respectively conducting said cooling fluid from said interior of said mixer and the constituents from said space.

4. In a mixing apparatus: a body having an exteriorly opening recess; a rotary chopper member guidingly carried by said body and having an operative portion seated in the recess; passage forming means opening into the bottom of said recess and in communication with the space between the chopper and the chamber wall for conducting materials to said space; said chopper member having a hollow interior opening axially of the chopper member at the opening of said recess; anda cap member detach-ably secured to said body; said members having annnlarly engaging surfaces preventing communication between the interior of said chopper member and said space; and means for conducting a cooling fluid into said hollow interior of said chopper member; said cap member having passage forming means respectively conducting said cooling fluid and said materials from said body.

5. in a mixing apparatus: a body having an exteriorly opening recess; a rotary shaft in the body having an axis aligned with the recess; a hollow chopper member seated in the bottom of the recess; an axially separable coupling between the shaft and the inner end of said chopper member; said chopper member having a. series of peripheral projections opposed to the walls of the recess; said body having passageways for conducting materials into the space between the projections and the recess and near the bottom of the recess; said chopper having at its outer end an annular wall and a port opening therethrough to the interior of said chopper member; a cap detachably secured to said body and having a surface annularly engaging said wall and maintaining said chopper member seated in the recess; said cap having one passageway communicating with said port and another passageway communicating with said space; and means forconducting a cooling fluid into said hollow chopper member.

6. In a mixing apparatus: a body having an exteriorly opening recess; a rotary shaft in the body having an axis aligned with the recess; a hollow chopper member having a stub shaft received in an aperture of the body aligned with the recess; means forming an axially separable connection between said shafts; said chopper member having a series of peripheral projections opposed to the walls of the recess; said body having passageways for conducting materials into the space between the projections and the recess and near the bottom of the recess; said chopper having at its outer end an annular wall and a port opening therethrough to the interior of said chopper member; a cap detachably secured to said body and having a surface annularly engaging said wall and maintaining said chopper member seated in the recess; said cap having one passageway communicating with said port and another passageway communicating with said space; said stub shaft having an axial passageway communicating with the interior of said chopper member, a peripheral annular groove, and ports interconnecting the groove and said axial passageway; and means for conducting a cooling fluid into said aperture at a place registering with said peripheral annular groove.

7. in a mixing apparatus: a support; means carried by the support and defining a pair of cylinders for constituent materials; a control cylinder carried by the support, and having a control piston; a pair of pistons cooperating with said material cylinders; means interconnecting said pistons for movement in unison; a pump detachably carried by the support for supplying fluid under pressure to said control cylinder; a rotary shaft for operating said pump; a body detachably carried by said support, and forming a mixing chamber, said body and said support having ports establishing communication between said material cylinders and said mixing chamber; a rotary mixer removably carried in the mixing chamber; an axially separable connection between said rotary mixer and said shaft; and a nozzle structure detachably carried by said'body for passing material from said mixing chamber, and for maintaining said mixer in said chamber.

8. In a mixing apparatus: means forming a mixing chamber; means forming a pair of spaces for constituent material; means for conducting materials from said spaces to said mixing chamber; fluid pressure means for applying 8 pressure to the materials in said spaces for urging said materials outwardly of the spaces, a pump casing; means forming a passage in said casing to supply fluid under pressure to said fluid pressure means; means forming a cylinder in said casing; a piston in said cylinder; a rotary shaft; means operated by the shaft for reciprocating said piston; means connecting said passage forming means to one side of said cylinder; means for supplying fluid to said cylinder; a check valve in said passage forming means; and a pressure relief means bypassing said passage upon the existence of a predetermined pressure in said connecting means to conduct fluid from said connecting means to said fluid supplying means.

9. In a mixing apparatus: means forming a mixing chamber; means forming a pair of spaces for constituent material; means for conducting materials from said spaces to said mixing chamber; fluid pressure means for applying pressure to the materials in said spaces for urging said materials outwardly of the spaces, a pump casing; means forming a passage in said casing to supply fluid under pressure to said fluid pressure means; means forming a cylinder in said casing; a piston in said cylinder; a rotary shaft; means operated by the shaft for reciprocating said piston; means connecting said passage forming means to one side of said cylinder; means for supplying fluid to said cylinder; at check valve in said passage forming means; and a rotary mixer in said mixing chamber and connected to said rotary shaft.

10. In a mixing apparatus: means forming a pair of cylinders in which constituent materials may be accommodated; a pair of pistons in the cylinders; a control cylinder having a positionable control piston connected to said pair of pistons for movement of said pair of pistons together with said control piston; said control piston forming first and second chambers on opposite sides of said piston; means forming a fluid reservoir; means forming first and second motor ports communicating with said first and second chambers respectively; means forming a pressure passage; an hydraulic apparatus for pumping fluid under pressure to said pressure passage from said reservoir; a control valve having two positions of operation, establishing communication optionally between said pressure passage and the motor ports respectively; and means responsive to the existence of a predetermined maximum pressure in said pressure passage for relieving the pressure in said passage.

11. In a mixing apparatus: means forming a pair of cylinders in which constituent materials may be accommodated; a pair of pistons in the cylinders; a control cylinder having a positionable control piston connected to said pair of pistons for movement of said pair of pistons together with said control piston; said control piston forming first and second chambers on opposite sides of said piston; means forming a fluid reservoir; means forming first and second motor ports communicating with said first and second chambers respectively; means forming a pressure passage; an hydraulic apparatus for pumping fluid under pressure to said pressure passage from said reservoir; a rotary shaft for operating said pump; means forming a mixing chamber receiving the material from said spaces; and a rotary mixer in the mixing chamber and connected to said rotary shaft.

12. in a mixer: means forming a mixing chamber; a rotary mixer in the chamber; means forming a reservoir space for material to be mixed, and communicating with the chamber; a member movable on the application of fluid pressure for urging the material in the space outwardly therefrom to the chamber; means for driving the mixer; and means operated by said driving means for creating fluid pressure for the movable member.

13. In a mixing apparatus: a body having a recess forming a mixing chamber; a hollow rotary mixer removably mounted in the recess and guided for angular movement about the axis of the recess, the mixer having an opening accessible at the opening of the recess; said body having first passage forming means for conducting material to be mixed to the recess exteriorly of the mixer; said body having second passage forming means for conducting a cooling medium to the hollow interior of the mixer; and a cap detachably carried by the body and covering the recess opening, said cap engaging the mixer about the mixer opening, said cap having ports registering with said mixer opening for passage of the cooling medium, said cap also having nozzle forming means registering with the recess opening exteriorly of the mixer for passage of the mixed material.

14. In a mixer: a support; a control cylinder having one end carried by the support, said control cylinder having walls provided with a longitudinally extending passageway; a first shell extending about the control cylinder and secured at one end to said support, said first shell forming With the exterior surface of said control cylinder a first cylinder space; a second shell extending about the first shell and secured at one end to said support, said second shell forming with the exterior surface of said first shell a second cylinder space; said cylinder spaces being adapted to receive constituent material to be mixed; a control piston within the control cylinder, said longitudinally extending passageway of said control cylinder opening within the control cylinder on that side of said control piston remote from said support; pistons respectively for said cylinder spaces; means interconnecting all of the pistons for movement in unison; means forming a mixing chamber for receiving material from said cylinder spaces; means carried by said support for creating fluid pressure; and means forming motor ports selectively eooperable with said fluid pressure means and communicating respectively with the control cylinder on that side 10 of said control piston adjacent said support and with said passageway.

15. In a mixing apparatus: a support; means carried by the support and defining a pair of cylinders for constituent materials; pistons for the cylinders respectively; fluid pressure operated means for moving the pistons in unison; a body detachably carried by the support, and forming a mixing chamber, said body and said support having ports establishing communication between said cylinders and said chamber; a rotary mixer removably carried in the mixing chamber; a rotary shaft carried by the support; an axially separable connection between the inner end of the mixer and said shaft; a discharge member detachably carried by said body for passing material from said chamber and for maintaining said mixer in said chamber; and means carried by the support for creating fluid pressure for said fluid pressure operated means.

References Cited in the file of this patent UNITED STATES PATENTS 539,055 Holthaus May 14, 1895 1,089,883 Trump Mar. 10, 1914 1,624,567 Teague Apr. 12, 1927 1,975,631 Bonfield Oct. 2, 1934 2,033,412 Chapman Mar. 10, 1936 2,056,931 Bannister Oct. 6, 1936 2,148,608 De Stubner Feb. 28, 1939 2,150,799 Jacuzzi Mar. 14, 1939 2,203,980 Burt June 11, 1940 2,238,864 Pratt et a1. Apr. 15, 1941 2,581,918 Spencer Jan, 8, 1952 

